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boot.s
42 lines (37 loc) · 1010 Bytes
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boot.s
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; Declare constants for the multiboot header.
MBALIGN equ 1 << 0 ; align loaded modules on page boundaries
MEMINFO equ 1 << 1 ; provide memory map
FLAGS equ MBALIGN | MEMINFO ; this is the Multiboot 'flag' field
MAGIC equ 0x1BADB002 ; 'magic number' lets bootloader find the header
CHECKSUM equ -(MAGIC + FLAGS) ; checksum of above, to prove we are multiboot
; Declare a multiboot header that marks the program as a kernel. These values are documented in the multiboot standard.
; The bootloader will search for this signature in the first 8 KiB of the kernel file, aligned at a 32-bit boundary.
section .multiboot
align 4
dd MAGIC
dd FLAGS
dd CHECKSUM
section .data
var dw 0
section .bss
align 16
stack_bottom:
resb 2048
stack_top:
section .text
extern monitor_write_dec
extern monitor_clear
global start:function (start.end - start)
extern main
start:
mov esp, stack_top
cli
call main
jmp $
.hang: hlt
jmp .hang
.end:
global hang
hang:
hlt
jmp hang